Color Ramp

IsekaiColorRamp is gradient mapping: it takes the brightness of every pixel and recolors it according to a gradient. Dark pixels get the color at one end of the ramp, bright pixels the color at the other end. This is the technique behind half the "cinematic color grade" looks on Instagram - teal shadows sliding into warm highlights. In ComfyUI you'd normally need a LUT node or a chunk of math to pull that off; here it's a dropdown with four presets.

How it works

The mechanism is a brightness-to-color remap. The image converts to a numpy array, its luminance drives the mapping, and each preset is a two-color gradient: Cool to Warm (blue-ish shadows to orange-ish highlights - the teal-and-orange look), Blue to Yellow, Purple to Orange (the "sunset film" grade), and Grayscale (brightness maps to black-to-white, a desaturate).

Honest limitation: you don't get to define your own colors. The four presets are fixed, and there's no color picker. So this is a quick-grade node, not a grading suite. Within that scope it's genuinely useful - Cool to Warm at low intensity is the fastest way I know to make a generated scene read "movie still." If you need arbitrary LUTs or custom ramp stops, look elsewhere; this won't stretch that far.

The intensity slider (0–1, default 1) blends the mapped result back against the original image. At 1.0 it's a full remap; at 0.3 it's a subtle wash. Because gradient mapping rewrites every pixel's color by brightness, it can crush midtone color into the ramp's palette fast - which is why the low-intensity route usually looks better than going full tilt.

The inputs

• image - the image to grade.
• preset - Cool to Warm, Blue to Yellow, Purple to Orange, or Grayscale.
• intensity - 0–1, default 1.

Output is a single image tensor. It's a late-stage node - after your other color work, before save.

Installing it

Ships in isekai-comfy-node:

ComfyUI Manager: search "isekai" → install isekai-comfy-node → restart. Manually:

cd ComfyUI/custom_nodes
git clone https://github.com/isekai-sh/isekai-comfy-node
cd isekai-comfy-node
pip install -r requirements.txt

Restart and it's under Isekai → Image/Blend. Pillow and requests are the only deps; no models, no downloads.

Where people get burned

The same batch caveat as every node in this pack: batched input gets only its first frame processed. And since the conversion runs through uint8 PIL, heavy intensity can show banding in smooth gradients - skies are where you'll notice it. Keep intensity moderate and it's a non-issue.

The bigger trap is expectations. Gradient mapping is a strong, opinionated effect, and the presets are what they are - you can't dial in your own brand colors. So try it at intensity 0.2–0.5 first. Full-strength Cool to Warm on an already-blue image will send everything into the same palette and flatten it. The node is a seasoning, not the whole meal, and it works best that way.